Examining Rats for Bubonic Plague - New Orleans, 1914
A group of rats on a ship at the Port of New Orleans died en masse in 1914, and were found to be infected with the bubonic plague. At the same time, a stowaway was killed in a card game, and brought to the morgue in a strange condition, discovered to be pneumonic plague - highly contagious from person-to-person.
A campaign of sulfonamide treatment, hospitalization, quarantine, and massive rat eradication was undertaken by city officials as soon as the news arrived.
For the next six years, the plague cropped up in small pockets of the city where rats were not well-controlled, and in the poorest slums where public officials didn’t care to venture. However, despite the continued infections cropping up, the management of the outbreaks was far more well-executed than the political and public relations catastrophe that was the San Francisco outbreak in 1900.
The 1950 movie Panic in the Streets was based off of this outbreak.
Read more about the plague in America at Puff the Mutant Dragon.